1 /*
2  * INET		An implementation of the TCP/IP protocol suite for the LINUX
3  *		operating system.  INET is implemented using the  BSD Socket
4  *		interface as the means of communication with the user level.
5  *
6  *		Definitions for the UDP module.
7  *
8  * Version:	@(#)udp.h	1.0.2	05/07/93
9  *
10  * Authors:	Ross Biro
11  *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12  *
13  * Fixes:
14  *		Alan Cox	: Turned on udp checksums. I don't want to
15  *				  chase 'memory corruption' bugs that aren't!
16  *
17  *		This program is free software; you can redistribute it and/or
18  *		modify it under the terms of the GNU General Public License
19  *		as published by the Free Software Foundation; either version
20  *		2 of the License, or (at your option) any later version.
21  */
22 #ifndef _UDP_H
23 #define _UDP_H
24 
25 #include <linux/list.h>
26 #include <linux/bug.h>
27 #include <net/inet_sock.h>
28 #include <net/sock.h>
29 #include <net/snmp.h>
30 #include <net/ip.h>
31 #include <linux/ipv6.h>
32 #include <linux/seq_file.h>
33 #include <linux/poll.h>
34 
35 /**
36  *	struct udp_skb_cb  -  UDP(-Lite) private variables
37  *
38  *	@header:      private variables used by IPv4/IPv6
39  *	@cscov:       checksum coverage length (UDP-Lite only)
40  *	@partial_cov: if set indicates partial csum coverage
41  */
42 struct udp_skb_cb {
43 	union {
44 		struct inet_skb_parm	h4;
45 #if IS_ENABLED(CONFIG_IPV6)
46 		struct inet6_skb_parm	h6;
47 #endif
48 	} header;
49 	__u16		cscov;
50 	__u8		partial_cov;
51 };
52 #define UDP_SKB_CB(__skb)	((struct udp_skb_cb *)((__skb)->cb))
53 
54 /**
55  *	struct udp_hslot - UDP hash slot
56  *
57  *	@head:	head of list of sockets
58  *	@count:	number of sockets in 'head' list
59  *	@lock:	spinlock protecting changes to head/count
60  */
61 struct udp_hslot {
62 	struct hlist_nulls_head	head;
63 	int			count;
64 	spinlock_t		lock;
65 } __attribute__((aligned(2 * sizeof(long))));
66 
67 /**
68  *	struct udp_table - UDP table
69  *
70  *	@hash:	hash table, sockets are hashed on (local port)
71  *	@hash2:	hash table, sockets are hashed on (local port, local address)
72  *	@mask:	number of slots in hash tables, minus 1
73  *	@log:	log2(number of slots in hash table)
74  */
75 struct udp_table {
76 	struct udp_hslot	*hash;
77 	struct udp_hslot	*hash2;
78 	unsigned int		mask;
79 	unsigned int		log;
80 };
81 extern struct udp_table udp_table;
82 extern void udp_table_init(struct udp_table *, const char *);
udp_hashslot(struct udp_table * table,struct net * net,unsigned num)83 static inline struct udp_hslot *udp_hashslot(struct udp_table *table,
84 					     struct net *net, unsigned num)
85 {
86 	return &table->hash[udp_hashfn(net, num, table->mask)];
87 }
88 /*
89  * For secondary hash, net_hash_mix() is performed before calling
90  * udp_hashslot2(), this explains difference with udp_hashslot()
91  */
udp_hashslot2(struct udp_table * table,unsigned int hash)92 static inline struct udp_hslot *udp_hashslot2(struct udp_table *table,
93 					      unsigned int hash)
94 {
95 	return &table->hash2[hash & table->mask];
96 }
97 
98 /* Note: this must match 'valbool' in sock_setsockopt */
99 #define UDP_CSUM_NOXMIT		1
100 
101 /* Used by SunRPC/xprt layer. */
102 #define UDP_CSUM_NORCV		2
103 
104 /* Default, as per the RFC, is to always do csums. */
105 #define UDP_CSUM_DEFAULT	0
106 
107 extern struct proto udp_prot;
108 
109 extern atomic_long_t udp_memory_allocated;
110 
111 /* sysctl variables for udp */
112 extern long sysctl_udp_mem[3];
113 extern int sysctl_udp_rmem_min;
114 extern int sysctl_udp_wmem_min;
115 
116 struct sk_buff;
117 
118 /*
119  *	Generic checksumming routines for UDP(-Lite) v4 and v6
120  */
__udp_lib_checksum_complete(struct sk_buff * skb)121 static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb)
122 {
123 	return __skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov);
124 }
125 
udp_lib_checksum_complete(struct sk_buff * skb)126 static inline int udp_lib_checksum_complete(struct sk_buff *skb)
127 {
128 	return !skb_csum_unnecessary(skb) &&
129 		__udp_lib_checksum_complete(skb);
130 }
131 
132 /**
133  * 	udp_csum_outgoing  -  compute UDPv4/v6 checksum over fragments
134  * 	@sk: 	socket we are writing to
135  * 	@skb: 	sk_buff containing the filled-in UDP header
136  * 	        (checksum field must be zeroed out)
137  */
udp_csum_outgoing(struct sock * sk,struct sk_buff * skb)138 static inline __wsum udp_csum_outgoing(struct sock *sk, struct sk_buff *skb)
139 {
140 	__wsum csum = csum_partial(skb_transport_header(skb),
141 				   sizeof(struct udphdr), 0);
142 	skb_queue_walk(&sk->sk_write_queue, skb) {
143 		csum = csum_add(csum, skb->csum);
144 	}
145 	return csum;
146 }
147 
udp_csum(struct sk_buff * skb)148 static inline __wsum udp_csum(struct sk_buff *skb)
149 {
150 	__wsum csum = csum_partial(skb_transport_header(skb),
151 				   sizeof(struct udphdr), skb->csum);
152 
153 	for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) {
154 		csum = csum_add(csum, skb->csum);
155 	}
156 	return csum;
157 }
158 
159 /* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
udp_lib_hash(struct sock * sk)160 static inline void udp_lib_hash(struct sock *sk)
161 {
162 	BUG();
163 }
164 
165 extern void udp_lib_unhash(struct sock *sk);
166 extern void udp_lib_rehash(struct sock *sk, u16 new_hash);
167 
udp_lib_close(struct sock * sk,long timeout)168 static inline void udp_lib_close(struct sock *sk, long timeout)
169 {
170 	sk_common_release(sk);
171 }
172 
173 extern int udp_lib_get_port(struct sock *sk, unsigned short snum,
174 			    int (*)(const struct sock *,const struct sock *),
175 			    unsigned int hash2_nulladdr);
176 
177 /* net/ipv4/udp.c */
178 extern int udp_get_port(struct sock *sk, unsigned short snum,
179 			int (*saddr_cmp)(const struct sock *,
180 					 const struct sock *));
181 extern void udp_err(struct sk_buff *, u32);
182 extern int udp_sendmsg(struct kiocb *iocb, struct sock *sk,
183 			    struct msghdr *msg, size_t len);
184 extern int udp_push_pending_frames(struct sock *sk);
185 extern void udp_flush_pending_frames(struct sock *sk);
186 extern int udp_rcv(struct sk_buff *skb);
187 extern int udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
188 extern int udp_disconnect(struct sock *sk, int flags);
189 extern unsigned int udp_poll(struct file *file, struct socket *sock,
190 			     poll_table *wait);
191 extern int udp_lib_getsockopt(struct sock *sk, int level, int optname,
192 			      char __user *optval, int __user *optlen);
193 extern int udp_lib_setsockopt(struct sock *sk, int level, int optname,
194 			      char __user *optval, unsigned int optlen,
195 			      int (*push_pending_frames)(struct sock *));
196 extern struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
197 				    __be32 daddr, __be16 dport,
198 				    int dif);
199 extern struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
200 				    __be32 daddr, __be16 dport,
201 				    int dif, struct udp_table *tbl);
202 extern struct sock *udp6_lib_lookup(struct net *net, const struct in6_addr *saddr, __be16 sport,
203 				    const struct in6_addr *daddr, __be16 dport,
204 				    int dif);
205 extern struct sock *__udp6_lib_lookup(struct net *net, const struct in6_addr *saddr, __be16 sport,
206 				    const struct in6_addr *daddr, __be16 dport,
207 				    int dif, struct udp_table *tbl);
208 
209 /*
210  * 	SNMP statistics for UDP and UDP-Lite
211  */
212 #define UDP_INC_STATS_USER(net, field, is_udplite)	      do { \
213 	if (is_udplite) SNMP_INC_STATS_USER((net)->mib.udplite_statistics, field);       \
214 	else		SNMP_INC_STATS_USER((net)->mib.udp_statistics, field);  }  while(0)
215 #define UDP_INC_STATS_BH(net, field, is_udplite) 	      do { \
216 	if (is_udplite) SNMP_INC_STATS_BH((net)->mib.udplite_statistics, field);         \
217 	else		SNMP_INC_STATS_BH((net)->mib.udp_statistics, field);    }  while(0)
218 
219 #define UDP6_INC_STATS_BH(net, field, is_udplite) 	    do { \
220 	if (is_udplite) SNMP_INC_STATS_BH((net)->mib.udplite_stats_in6, field);\
221 	else		SNMP_INC_STATS_BH((net)->mib.udp_stats_in6, field);  \
222 } while(0)
223 #define UDP6_INC_STATS_USER(net, field, __lite)		    do { \
224 	if (__lite) SNMP_INC_STATS_USER((net)->mib.udplite_stats_in6, field);  \
225 	else	    SNMP_INC_STATS_USER((net)->mib.udp_stats_in6, field);      \
226 } while(0)
227 
228 #if IS_ENABLED(CONFIG_IPV6)
229 #define UDPX_INC_STATS_BH(sk, field) \
230 	do { \
231 		if ((sk)->sk_family == AF_INET) \
232 			UDP_INC_STATS_BH(sock_net(sk), field, 0); \
233 		else \
234 			UDP6_INC_STATS_BH(sock_net(sk), field, 0); \
235 	} while (0);
236 #else
237 #define UDPX_INC_STATS_BH(sk, field) UDP_INC_STATS_BH(sock_net(sk), field, 0)
238 #endif
239 
240 /* /proc */
241 int udp_seq_open(struct inode *inode, struct file *file);
242 
243 struct udp_seq_afinfo {
244 	char				*name;
245 	sa_family_t			family;
246 	struct udp_table		*udp_table;
247 	const struct file_operations	*seq_fops;
248 	struct seq_operations		seq_ops;
249 };
250 
251 struct udp_iter_state {
252 	struct seq_net_private  p;
253 	sa_family_t		family;
254 	int			bucket;
255 	struct udp_table	*udp_table;
256 };
257 
258 #ifdef CONFIG_PROC_FS
259 extern int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo);
260 extern void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo);
261 
262 extern int udp4_proc_init(void);
263 extern void udp4_proc_exit(void);
264 #endif
265 
266 extern void udp_init(void);
267 
268 extern int udp4_ufo_send_check(struct sk_buff *skb);
269 extern struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
270 	netdev_features_t features);
271 #endif	/* _UDP_H */
272